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Hedgehog signalling maintains the optic stalk-retinal interface through the regulation of Vax gene activity
SMAD3 or Mothers against decapentaplegic homolog 3
+: S×S → S
The article shows a march of ideas, grounded in constraints such as truth, validity, reproducibility etc. and a lessening of the need to exalt one concept over another, except perhaps for our own attention and other resources. Might this be an explicit entry for part of the article. Deduction only yields to Deduction or Induction; Jevon's Plausibility of a Conjecture becomes a defensible effort rather than a waste of time; Evidence becomes just as important as Authority. Should we also include Wittgenstein's concept of the usefulness of Contradiction and Turing's rejection of that discussion? Would that not also allow the entrance into the speculative sciences, to use Roger Bacon's terminology.
These questions may be more appropriate for a philosophical article; in that case we could ignore them; would that be appropriate for a history article? In Max Born, Natural Philosophy of Cause and Chance, Born points out that Cause and Effect can be analyzed no further than that of a mathematical function. Thus he removes them as things to be found like mountains in terra incognita. This removes considerations such as 'First Movers' etc. and considerably simplifies discussions.
Ernst Mach makes a similar point about scientific law; our laws are psychologically dependent, like Occam's Razor. It helps us to simplify and otherwise transform the subjects of discussion, in order to manipulate their properties, and perhaps understand them better. Thus the laws of physics are simple, but the complication lies in the specification of the boundary conditions of the models.
In the twentieth century, statistics and computers came into their own, and we need no longer find only analytic solutions to mathematical functions, instead other techniques such as simulation by the Monte Carlo method were used to build things like bombs, etc.
On another philosophical point, Isaac Newton formulated laws of nature with forces to which we and Nature are subject. This is framed exactly like Roman law in which law started out as sacred mystery, to be passed in secret from father (patriarch) to son (but with a bow to vengance as a motivation for punishing transgressors of law). Then the plebeians demanded equal access to the law and their publication in the Twelve Tables. (Sounds like Wikipedia from 2200 years ago, doesn't it.) The analogy appears to be the personal dependence of scientific method on who is performing the steps. This concept is stated explicitly in the scientific method article itself, as well as the caution that scientific method is not a recipe and requires ingenuity and imagination. What is left unsaid is that it takes a special person to practice scientific method. Is this obvious to those reading a history? Does history take special people only? Is the historical fact that scientists have shown high moral development as well as the ability to maintain a neutral/ objective POV? Might this be myth? Is it possible for scientists to demonstrate that they only are able to practice scientific method? Might that be a litmus test?
There is a parallel situation in mathematics; it takes a mathematician to construct a mathematical proof, although a proof ought to be accessible to non-mathematicians. We do not yet understand how to make ingenuity and understanding methodical enough to satisfy Francis Bacon's dream of a better method. --Ancheta Wis 17:23, 10 February 2007 (UTC)
scholasticism Divine right and Roman law Roman law Oersted We need a community here. Failing that someone might just post this on Craigslist.org: "Wanted: nobel-level leader and expert in physics to devote countless hours on Free stuff. Wikiproject stalled for lack of community." or take it to the community for comment or maybe The Onion. Come on. --1 February 2007 (UTC)
What about setting a timer. After one week, one month, one year, 10 years, 100 years, ... declare the project dead. Draw a Black outline around the article/wip: "This effort is archived for historical purposes only. Please do not modify it." Then forbid any efforts to try again. 09:47, 1 February 2007 (UTC)
This discussion is evidence that the page/wip is dead for want of moderation. That this page not be a total loss, you (the reader) might try the Autobiography of Benvenuto Cellini. Benvenuto Cellini was an extremely talented man of the Renaissance who had the ill-fortune to create works which were in high demand, and who was forced to defend himself, to put it charitably (he had to kill people who wanted to steal from him). I first learned of him through music: Benvenuto Cellini (opera). -- 1 February 2007 (UTC)
11:04, 29 January 2007 (UTC)
27 November 2007 I am struck by the similarity the situation on this physics/wip page and the disorder of autism.
This weekend, CNN broadcast a program, Autism is a World, featuring an autistic person, Susie Rubin, of Los Angeles, California. Susie Rubin carries spoons at all times. When she must, she watches the flow of water from a tap and modulates its flow with the spoons. At such times, she has stated that she ceases to think. Susie Rubin literally did not think until she learned how to use a communicator after 13 years of dysfunctional communication. She states "my mind woke up" after her use of the communicator.
A communicator is an electronic device with a keyboard which serves to rule out words as you type in letters, and which simultaneously allows you to select appropriate words in your message. This is very similar to the use of lexigram keyboards by some research primates in the US, who have learned to communicate words to humans and to each other[1].
Susie Rubin is afflicted with developmental problems, but the use of the communicator and a 24-hour/day support-person are allowing her to attend Whittier College.
Susie Rubin has behaviors which interfere with communication. She will not look at those who are speaking to her. Her face distorts with the effort of conversation. The subtleties of ordinary communication cannot be observed when attempting to communicate with her, and one must devote extra effort if one wishes to succeed with her. In communications terms, it is as if she has multiple broadcast channels which she cannot suppress even when highly educated people are devoting their full attention to her in conversation. At least one channel of her mind is attempting to attend to such conversation. The use of her communicator proves that she is in fact listening and can respond.
On this physics/wip page, a thread of conversation, asynchronous to the stated goal under discussion will pop-up, between individuals, sometimes antagonist, sometimes cooperative, as observed previously by several people.
It is as if the boiler on a steam engine were suddenly doused with cold water, suddenly lowering the temperature, and destroying the ability of the engine to do work.
This is the reason that I have proposed that we use an alternative page for the article, and the talk page for talk, rather than attempting to restrict work on the WIP page until consensus is reached. A normal wikipedia page works this way, after all. Is it not obvious that the protocol of reverting all edits to the WIP page has dampened the ability of editors to work?
I am pretty sure you are sincere in your comments; just wanted you to know my opinion of the Physics/wip project. I believe that it is a fundamental error in the structure of the project, to mix up talk with the article edits. I have raised this with SFC9394 who appears to wish that this project run on autopilot. Well, I think it pretty clear that a commitment to active moderation is a necessity for the project.
How would you like to be the moderator. You appear to enjoy the word-end of the article. If you like, I can nominate you, but I am not positive that others would like to see a change in the project. In particular, I believe that MichaelMaggs has an interest in keeping the project as is. But if that is the case, then I believe that this project will simply be an example of what not to do and how not to do it.
If you are interested, I will broach the possibility with MichaelMaggs and SFC9394 in particular.
Now this has a side-effect, of which I am perfectly aware. The assumption of the role of moderator will of necessity lessen the time available for direct editing. Having studied this topic for over 40 years now, (with some heavy-duty people, Nobel laureates, founders of industries, etc.) I just want the pleasure of writing about physics, so I am selfish about wanting to remain on the editing side. And I am sincere about collaborating. That is one of the problems with the current project. We are not currently collaborating, by the design of the project. Thus no wiki-action.
My background is one reason I define a physicist as one who has discovered new physics. I leave open the definition of scientist as one who is engaged in the systematization of scientific knowledge, using scientific method. By that definition, everyone working on the page is a scientist, and my teachers are all physicists. --Ancheta Wis 23:06, 22 November 2006 (UTC)
In geophysics, the Dahm discontinuity [1] is a sharp discontinuity overlying a 200-km-thick low-velocity layer just above the Earth's core. Cornelius Dahm found this from seismographic data on the Tango, Hawke Bay, and Long Beach earthquakes, all of 10–12 km. focal depth, at the geophysics department at Saint Louis University, Saint Louis, Missouri, under the direction of James B. Macelwane, S.J..
There is no formal definition of physics; many people have their own definitions in order to satisfy their specific requirement. Some definitions of physics include:
1. Rutherford's Definition
"All science is either physics or stamp collecting" --Ernest Rutherford [D]
[D] Ernest Rutherford in J. B. Birks Rutherford at Manchester (1962)
8 words.
84 word paraphrase: Science is not merely a collection of facts, but more importantly, a consistent, coherent structure of interconnected results which follow scientific method.
At the time Rutherford spoke, only physics could claim this position. Anything else became a series of ad-hoc positions (stamp collecting: matter, energy, atoms, penguins). Biology had not yet discovered the structure of DNA; the atoms of chemistry had not yet been explained by quantum mechanics. Progress has come by using the constructs of physics.
Confer with Joshua Davis' statement included in #Position B.
1. Einstein's Definition
"Physics constitutes a logical system of thought which is in a state of evolution, and whose basis cannot be obtained through distillation by any inductive method from the experiences lived through, but which can only be attained by free invention." [E]
39 words - [E] Albert Einstein (1936), Physics and Reality, summarized in his Essays in Physics (1950) New York, Philosophical Library p. 51
Confer with Noetica's and Krea's statements above. I do not have a copy of Einstein's Ideas and Opinions which actually dovetail with Position B above. --Ancheta Wis 01:56, 25 November 2006 (UTC)
"[The] general laws on which the structure of theoretical physics is based claim to be valid for any natural phenomenon whatsover. With them, it ought to be possible to arrive at the description, that is to say, the theory, of every natural process, including life, by means of pure deduction ... " [E2]
48 words. [E2] Albert Einstein (1918, Max Planck's 60th birthday) "Principles of Research" in Ideas and Opinions, ISBN 0-517-55601-4 (1954) p.226. --Ancheta Wis 08:24, 29 November 2006 (UTC)
Space or distance, length
Unit | Exponent | Example | F |
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Time or duration
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Mass or measure of matter
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Charge a property of matter
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Frequency Feynman 1 2-5
Units of Hertz, or oscillation/sec
Units | Exponent | Example | Construct |
1 | 10^2 | Electric field | field |
5 | 10^5 - 10^6 | Radio | wave |
5 | 10^14 - 10^15 | Light | wave |
1 | 10^27 | Cosmic rays | particle |
Energy
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Temperature
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Entropy
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By 1798, Benjamin Thompson (1753-1814) had discovered that work could be transformed to heat without limit - a precursor of the conservation of energy or
In 1824 Sadi Carnot (1796-1832) scientifically analyzed the steam engines with his Carnot cycle, an abstract engine. Rudolf Clausius (1822–1888) noted a measure of disorder, or entropy, which affects the continually decreasing amount of free energy which is available to a Carnot engine in the:
Thus the continual march of a thermodynamic system, from lesser to greater entropy, at any given temperature, defines an arrow of time. In particular, Stephen Hawking identifies three arrows of time[1]:
Entropy is maximum in an isolated thermodynamic system, and increases. In contrast, Erwin Schrödinger (1887–1961) pointed out that life depends on a "negative entropy flow"[2]. Ilya Prigogine (1917–2003) stated that other thermodynamic systems which, like life, are also far from equilibrium, can also exhibit stable spatio-temporal structures. Soon afterward, the Belousov-Zhabotinsky reactions [3] were reported, which demonstrate oscillating colors in a chemical solution[4]. These nonequilibrium thermodynamic branches reach a bifurcation point, which is unstable, and another thermodynamic branch becomes stable in its stead[5]. "Suppose that we have a chemical reaction {A} ↔ {X} ↔ {F} in which {A} is a set of initial products, {X} is a set of intermediate products, {F} is a set of final products. At equilibrium, we have a detailed balance where there are as many transitions from {A} → {X} as from {X} → {A}, with the same applying to {X} and {F}. the ratio {A}/{F} takes on a well-defined value if the system is isolated. Now consider an open system. There are many solutions for {X} for given {A} and {F}, but only one corresponds to maximum entropy. This solution, which we call the "thermodynamic branch" may be extended to the domain of nonequilibrium, but that this branch becomes unstable at some critical distance from equilibrium. The point at which this occurs is known as the bifurcation point. Beyond the bifurcation point, a set of new phenomena arises"[6].
Instrumentalism takes the view that a scientific theory is only as good as its predictions. Furthermore, the explanatory power of that theory is immaterial. Deutsch deplores this view.[7]. Rather, Deutsch hypothesizes a multiverse of spacetimes; that space be a series of snapshots at a moment in the universe and time be a sequence of moments which index those snapshots[8]. But that sequence of moments is known in principle only beginning from the Planck epoch, 5*10-43 seconds 'after' the Big Bang, which occurred an infinity of cosmological decades before it. This viewpoint is a consequence of general relativity: there are an infinity of worlds and an infinity of moments.
Einstein would not have accepted Deutsch' viewpoint. Rather, Einstein accepted only the single static universe, and modified the Einstein field equations to reflect this. But in 1927, Georges LeMaître argued, on the basis of general relativity, that the universe originated in a primordial explosion. At the fifth Solvay conference, that year, Einstein brushed him off with "Vos calculs sont corrects, mais votre physique est abominable"[9]. In 1929, Hubble announced his discovery of the expanding universe.
Image:COBE cmb fluctuations.gif p252
"Near the beginning (or end) of the universe, everything would be squeezed into an exotic state that mixes up the dimensions of "space" and "time". [At] ... the Planck time there is then a firm barrier. On this tiny scale, some theories, going back to Wheeler's pioneering ideas in the 1950s, suggest that the time dimension was intermingled with the three spatial dimensions into a froth of "space-time foam"."[10] "Penrose thinks times arrow is orientated by the difference between the dynamics of the big bang and the big crunch."[11] But note this does not account for hyperinflation. Penrose's twistors - space and time are composed of interlaced light cones. p265
Monkey Forest is a Hindu temple in Bali. The temple is an open-air forest, symbolizing birth (at the lowest level), middle life (at the entrance), and death (at the highest level on the top of the mountain)
6,886,080 articles as of 08:22 (UTC) Sunday, September 22, 2024 New pages showing that at 07:19, August 4, 2005 (UTC), the 666 666th article was either James Robson (from the Oz (television series)) or Jason Goes To Hell: The Final Friday
{{PhysicsTOC}} 1. Definition -- See list of topics to the right, or see the categories
1.1 Originally, physics (from the Greek, φύσις (phúsis), "nature" and φυσική (phusiké), "knowledge of nature") was the science of nature[1] [2].
1.2 Over the course of twenty-five hundred years, physics has become known for a series of fundamental laws[3]. Called natural philosophy[4] [5], physics was the science for identifying the constituents of the natural world[6].
1.2.1 The role of energy was identified by the eighteenth century, and precisely defined by the nineteenth century.
1.2.2 The atom[7] of matter was successfully subsumed into the infrastructure of the sciences, which are indebted to physics. During this time, science became professionalized and specialized; physical explanations for various complex systems were formulated, for chemistry[8], for biology[9],[10], and more recently for neuroscience[11].
1.2.2.1 Now that E=mc² has publicized the equivalence of matter and energy, any definition of the mass noun "matter" must also state the energy levels involved in that physical system, for matter can be created or destroyed, at the cost of that energy.
1.2.3 The role of information, or negative entropy in a open system was first recognized in physics in the late nineteenth century and explicated in the twentieth century, with expression in engineering hardware, software agents, and in biological systems, in our time.
1.3 It is difficult to state a prospective or even current definition for physics, for each researchers' focus defines their subject of study. Thus we can talk retrospectively of Galileo's physics or Einstein's physics, but we cannot talk of a current researcher's physics, or a future researcher's physics without determining their philosophy[12] [13] . For example, Murray Gell-Mann's contribution to complex systems should be noted[14].
1.3.0.1 In an aggregate definition of physics, such as in a list of items (in the TOC at right), the items serve to name something which is incompressible, which cannot be further reduced, such as the Greek concept of the atom of matter. This was Newton's conception of matter. But physics has discovered energy regimes where atoms have parts, and the definition of fundamental can then be questioned, for the energy regime must also be stated for such a definition to hold, whether it be room temperature or kelvin at the instant of the big bang.
1.3.0.2 But an aggregate need not have tensile strength; then the slightest pull would separate the components. Thus a proper definition of physics should also include a unifying agent, to bind it into a subject.
1.3.0.3 One candidate for that unifier is Nature itself. Nature, to man, seems welcoming, our home, the source of our life. But overall, the universe is hostile to life and to us. Indeed, life itself is a huge competition of life-forms for their individual advantage. And Nature, with its enormous powers, can be hostile to us as well. Thus we cooperate in symbiosis to survive it.
1.3.0.3.1 Earth is part of that Nature which holds us. But Earth is built largely from iron, an ash of stellar nucleosynthesis in the burning of the stars; thus our earth is composed of stellar ash, and we were made from the stars, because gravitation kept the elements from which we were made on this planet. The lighter elements which we breathe are kept here by virtue of gravitation. One of the problems in the exercise books of the Feynman Lectures on Physics asks "what is the probability that we have drunk from the water which our forebears drank?" and the answer depends on your philosophy.
1.3.1 Physics itself is further developing, both inward (beyond the atomic nucleus, which requires the use of ever-higher energy regimes) and outward (by consideration of the circumstances for big bangs and the development of our own universe from the multiplicity of multiverses which could have been ours). But the two realms are currently not unified under one theory.
Physics need not be considered an arcane or difficult subject. Classical mechanics can be amply illustrated on children's playground equipment or in a sports stadium. Read on for more --
Note to the reader: You may, without loss of generality, skip any point marked by a bullet below, e.g.
2. Introduction
3. History & Foundations
4. Principles/Concepts
5. Current Topics/Current Research
6. Applications and Influence
7. References and Notes
8. External Links
Word counts:
1.3.0.x -- 150 words
Further development from a tutorial point of view might place the physics of the playground (i.e., classical mechanics) under section 3 or section 4 depending on consensus.
Interrelationships of the topics of physics might go in section 3 or section 4 depending on consensus.
Some of the contributions to complex systems by Murray Gell-Mann and others might be placed in section 5.
It would be a shame not to highlight David R. Ingham's venn diagram for physics.
It appears that the theses of Petrarch and Gibbon, who witnessed shepherds grazing their flocks among the ruins of Rome is under attack. Thus a Roman-centered view of the development of western civilization is POV. Fine. The counter-argument appears to be that the medieval universities were the truth-bearers. They started the infrastructure which we need for scientific communities; these universities produced thinkers like Robert Grosseteste (1175 - 1253), Roger Bacon (1214 – 1294), Albertus Magnus (1193-1280), Duns Scotus (1266 – 1308), William of Ockham (1285–1349), and Jean Buridan (1300 - 1358) . Thus the disputed sentence might be replaced with
After years of chasing craigslist.org, our website has managed to cross places with the classified ads provider, as Alexa shows that today we are now at #31 in the world vs #34 for craigslist. Will the trend continue? Is this for today only? Their weekly average is 32 and ours is 34. But who's counting? Might this be a variant of editcountitis? And the blind test has shown that the category bar has no correlation with the rise; the only way to prove there is a correlation with the #31 is to remove the browsebar. Ancheta Wis 22:18, 20 October 2005 (UTC)
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This is a simple enough beginning and a start. But generally, in an introduction, we set the stage. That is, we give context before we state content. Are we agreed that the context of this term is philosophical? If not, might there be a manifold context, namely the psychological, ethical, practical, theological, and spiritual views, as well as philosophical? If so, where is the discussion of the more fundamental context? What article contains this more fundamental view? Is this the very article which must contain that view? In other words, where is the ontology for this article? Simply dealing with true as a predicate with value 1, doesn't say half of it; there is more to the meaning. The connotation for truth is that someone has thought about it, and that others can reliably depend upon it. It appears there are manifold views of truth. If we were to view truth as a jewel, and the different angles from which we view that jewel as "views of truth", then the nature of truth can be called unitary.
I am not trying to stir up trouble. My personal use of this article is as a foundation article for my own interests. As a user, truth is something I depend upon. I happily defer to those who can speak about it. Ancheta Wis 15:10, 24 September 2005 (UTC)
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